Ask Milo – Isolation tank

Gabrielle submitted the following question:I’m purchasing two hermit crabs soon. I keep reading that I need an isolation tank, but I really don’t have the space or funds for one. Is there anything I can do for molting crabs without purchasing a whole new isolation tank? If not, do you have any recommendations on how to do it as cheaply as possible? I’ve spent so much money on their regular supplies already haha. Thank you!

Dear Gabrielle,

Setting up a crabitat can be expensive. An isolation tank can be a smaller tank that fits within your larger tank. It doesn’t need to be a full size tank. It is best if you do have a full size isolation tank, though, as new hermit crabs often need to relax after post purchase stress (PPS) and may be traumatised by interactions with other land hermit crabs. Most newly purchased crabs will either dig down and hide for a while or head to the food and water bowl and then dig down. It depends on the conditions they were in before you bought or adopted them from. They can surprise crabs that are already moulting, which would be bad.

Since you are worried about molting crabs and not new crabs right now, you can use an in place isolation. For a surface molter this can be accomplished by cutting the bottom off of a 2L plastic bottle and then placing it over the molter and pushing it down (gently!) into the substrate, all the way to the bottom of your tank if possible. This will keep tank mates from cannibalizing the molter while it is soft and defenseless. Remove the lid from the bottle top to allow air flow. If you can’t get the bottle all the way to the bottom of the tank, keep an eye out for signs of other crabs trying to burrow their way in.

Another easy isolation unit for a molting hermit crab can be a small Kritter Keeper or Living World Small Pals Pen.

It has a lid to close to keep the other hermit crabs out and has enough area for some sand, scallop shell for food and another for water. When the hermit crab is finished molting you can lift the lid up and other hermit crabs may dig down to moult in it. It doesn’t take up a lot of surface area and you can put it on a second level if you have one.

Another option is a Gladware bowls that you can buy at the dollar store. The lids are thin plastic that you can poke holes in. They are a great humid hides in your tank. Another solution is to check out Garage/Tag/Yard sales, eBay, Craigslist and other online sites for second hand 10 Gallon or 20 Gallon fish tanks. They are often cheap and good to have on hand. If you are in Australia then Gumtree is also a good resource. Good luck!